When consumed orally in normal amounts, ginko biloba extract is safe for most people, according to MedlinePlus. Although safe, there is the possibility of side effects, such as allergic skin reactions, constipation, upset stomach, dizziness and headaches for some people when ingesting ginko biloba extract.
Crude ginko plant, roasted ginko seeds or fresh ginko seeds may be harmful if consumed in large amounts. If an individual eats as many as 10 roasted seeds a day, he may experience shock, a weak pulse, seizures and may also have a difficult time breathing. The fresh seeds belonging to the ginko plant are extremely toxic and can cause death if ingested, as stated by MedlinePlus.